Computing networks provides a fundamental and important communications and distributed-computing medium within many different large commercial and governmental organizations as well as within small businesses and homes. Virtual private networks (“VPNs”) allow geographically separated local computer networks to be interconnected through any of various public communications media, including the Internet, without compromising the security of the local networks and without changing the basic communications interfaces and addressing schemes used within the local networks. In the case of Internet-based VPNs, Internet-connected VPN provider-edge devices, including Internet routers (“PE devices”) interface to customer-edge devices (“CE devices”), generally local-area-network routers, to provide interconnection of CE devices and the local networks in which they are included. VPN providers often need to automatically assemble a data representation of networks within which they provide VPNs, including characterization of the various CE devices and corresponding PE interfaces to which they interface. However, because the Internet addresses used by CE devices are not determined by VPN providers, it may be difficult for a VPN-provider management system to correctly assemble a correct and unambiguous data representation of a network environment. VPN providers, VPN customers, and many other people working in roles involved with computer networking and VPN provision continue to seek new and better automated methods for assembling data representations of networking environments.